Field of the Invention
The present invention relates to an image forming apparatus, a control method therefor, and a storage medium, and in particular to an image forming apparatus that displays a remaining amount of sheets, a control method therefor, and a storage medium.
Description of the Related Art
An MFP which is an image forming apparatus carries out a printing process using sheets, which are fed from a plurality of sheet feeding cassettes and an external sheet feeding deck which are sheet feeding units, as recording sheets. The sheet feeding deck is capable of storing a larger amount of sheets than the sheet feeding cassettes are, and thus, for example, used to make a large amount of copies at once.
There is also known a sheet feeding apparatus which has a plurality of, for example, two stacking units, in which sheets are stacked when they are stored, as sheet feeding units capable of storing a much larger amount of sheets (hereafter referred to as “the large-capacity sheet feeding apparatus”). In the large-capacity sheet feeding apparatus, one stacking unit (hereafter referred to as “the sheet feeding stacking unit”) has a sheet feeding port for feeding sheets, and sheets stacked in the sheet feeding stacking unit are fed from the sheet feeding port. When sheets stacked in the sheet feeding stacking unit have run out, the large-capacity sheet feeding apparatus moves sheets stacked in the other stacking unit (hereafter referred to as “the sheet non-feeding stacking unit”) having no sheet feeding port for feeding sheets (see, for example, Japanese Laid-Open Patent Publication (Kokai) No. 2009-263014).
In a conventional sheet feeding apparatus, a remaining amount of sheets is displayed on a display unit or the like provided in an MFP so that a user can see a remaining amount of sheets stored in the sheet feeding apparatus. A remaining amount of sheets is calculated based on a remaining amount of sheets stacked in a stacking unit and displayed on the display unit of the MFP. On the display unit, a remaining amount of sheets is displayed using a plurality of, for example, three remaining amount bars, and the number of remaining amount bars is determined based on a remaining amount of sheets in the sheet feeding apparatus. Based on the number of remaining amount bars displayed on the display unit, the user determines whether or not to replenish sheets.
However, in the large-capacity sheet feeding apparatus having the sheet feeding stacking unit and the sheet non-feeding stacking unit described above, when the sheet feeding stacking unit and the sheet non-feeding stacking unit are replenished with sheets based on a remaining amount of sheets in the large-capacity sheet feeding apparatus which is displayed on the display unit, the sheets may not be properly replenished. Here, when a certain amount of sheets have been fed from the sheet feeding stacking unit, a remaining amount of sheets in the large-capacity sheet feeding apparatus is calculated based on a remaining amount of sheets in the sheet feeding stacking unit and remaining amount of sheets in the sheet non-feeding stacking unit, and based on the calculated remaining amount of sheets in the large-capacity sheet feeding apparatus, the number of remaining amount bars displayed on the display unit decreases. In this case, it can be considered that a user replenishes the sheet feeding stacking unit and the sheet non-feeding stacking unit with sheets so as to prevent sheets in the sheet feeding stacking unit and the sheet non-feeding stacking unit from running out. However, for example, when the user replenishes the sheet feeding stacking unit with sheets in a state where sheets are stacked in the sheet non-feeding stacking unit, the sheets stacked in the sheet non-feeding stacking unit retain in the sheet non-feeding stacking unit without being moved to the sheet feeding stacking unit. Here, when the user repeatedly replenishes the sheet feeding stacking unit with sheets, the sheets continue to retain in the sheet non-feeding stacking unit. As the sheets continue to retain, they degrade due to humidity and passage of time, and hence the user needs to determine the appropriate timing for replenishing sheets with consideration given to retention of sheets in the sheet non-feeding stacking unit.